In 3GPP (3rd Generation Partnership Project), W-CDMA (Wideband Code Division Multiple Access) mode is standardized as a third-generation cellular mobile communication mode and the service is sequentially started (see, e.g., non-patent document 1). One CDMA mode is a spread spectrum mode of FDD with 5-MHz radio frequency bandwidth, and radio physical channels are differentiated by spread codes and code-multiplexed for transmission in the same radio frequency bandwidth.
The W-CDMA mode includes a radio link from the mobile station to the base station (hereinafter, uplink) and a radio link from the base station to the mobile station (hereinafter, downlink). The uplink and the downlink include logical channels (Logical Channel) at SAP (Service Access point) between a layer 3 and a layer 2, transport channels (Transport Channel) for providing service from a layer 1 to the layer 2, and physical cannels (Physical Channel) defined as a transmission channel between radio nodes (base station and mobile station) of the layer 1 for implementing transmission through the transport channel with the use of an actual radio transmission path (see, e.g., non-patent document 2).
The physical channels of the downlink of the W-CDMA are a common pilot channel CPICH (Common Pilot Channel), a synchronization channel SCH (Synchronisation Channel), a paging indicator channel PICH (Paging Indicator Channel), a primary common control physical channel P-CCPCH (Primary Common Control Physical Channel), a secondary common control physical channel S-CCPCH (Secondary Common Control Physical Channel), a downlink dedicated physical data channel DPDCH (Dedicated Physical Data Channel), a downlink dedicated physical control channel DPCCH (Dedicated Physical Control Channel), an acquisition indicator channel AICH (Acquisition Indicator Channel), etc.
The physical channels of the uplink of the W-CDMA are a physical random access channel PRACH (Physical Random Access Channel), an uplink dedicated physical data channel DPDCH, and an uplink dedicated physical control channel DPCCH.
In the downlink of the W-CDMA, the primary common control physical channel P-CCPCH includes a broadcast channel BCH (Broadcast Channel) of the transport channel, and the secondary common control physical channel S-CCPCH includes a forward access channel FACH (Forward Access Channel) and a paging channel PCH (Paging Channel). The downlink dedicated physical data channel DPDCH includes a downlink dedicated channel DCH (Dedicated Channel) of the transport channel.
In the uplink of the W-CDMA, the physical random access channel PRACH includes a random access channel RACH (Random Access Channel) of the transport channel, and the uplink dedicated physical data channel DPDCH includes an uplink dedicated channel DCH (Dedicated Channel).
A high-speed downlink packet wireless access HSDPA (High Speed Downlink Pcket Access) (non-patent document 3) mode is standardized that applies the downlink of the W-CDMA mode to high-speed packet communication.
The downlink physical channels of the HSDPA mode are a high-speed physical downlink shared channel HS-PDSCH (High Speed Physical Downlink Shared Channel) and an HS-DSCH-related shared control channel HS-SCCH (HS-DSCH-related Shared Control Channel).
The uplink physical channels of the HSDPA mode includes an HS-DSCH-related uplink dedicated physical control channel HS-DPCCH (Dedicated Physical Control Channel for HS-DSCH).
In the downlink of the HSDPA, the high-speed physical downlink shared channel HS-PDSCH includes a high-speed downlink shared channel HS-DSCH (High Speed Downlink Shared Channel) of the transport channel.
The outline of the major physical channels and transport channels of the W-CDMA will then briefly be described.
The common pilot channel CPICH is a downlink common channel existing in each cell and is mainly used for propagation path status estimation (Channel Estimation) of downlink channels, cell selection for mobile stations (Cell Search), and timing reference of other downlink physical channels in the same cell, etc.
The synchronization channel SCH is a downlink common channel existing in each cell and is used in the initial stage of the mobile-station cell search.
The paging indicator channel PICH is a downlink common channel forming a pair with a paging channel PCH (Paging Channel) of the transport channel corresponding to the secondary common control physical channel S-CCPCH having a paging signal mapped thereon and transmits the presence or absence of voice-call (CS: Circuit Switch) or packet-call (PS: Packet switch) incoming-call information for incoming call groups that are groups of mobile stations. When a mobile station belonging to an incoming call group #n is notified of the presence of an incoming call for the incoming call group #n through the paging indicator channel PICH, the mobile station receives the paging channel PCH in the corresponding radio frame mapped on the secondary common control physical channel S-CCPCH to determine the presence or absence of the incoming call.
The paging indicator channel PICH is a channel set with the aim of reducing a discontinuous reception IR (Intermittent Reception) rate for improving battery saving in the mobile stations. The paging indicator channel PICH transmits a short paging indicator PI (Paging Indicator) for notifying the mobile stations of the presence or absence of an incoming call to the mobile stations belonging to the incoming call group #n and the mobile stations normally receive only the paging indicator PI in a standby state (idle mode). Only when the mobile station is notified of the presence of an incoming call through the paging indicator PI, the mobile station receives the paging channel PCH corresponding to the paging indicator PI.
Since the paging indicator PI is allocated to a plurality of the incoming call groups #n and a reception frequency per incoming call group #n can extremely be lowered, the mobile station in the standby state (idle mode) may receive only the short paging indicator PI, which can extremely reduce the frequency of receiving the paging signal of the long paging channel PCH (having a large amount of information).
The primary common control physical channel P-CCPCH is a downlink common channel existing in each cell and has a broadcast channel BCH (Broadcast Channel) of the transport channel mapped thereon to transmit broadcast information such as system information and cell information.
The secondary common control physical channel S-CCPCH is a downlink common channel and a plurality of these channels can exist in each cell. The forward access channel FACH (Forward Access Channel) and the paging channel PCH (Paging Channel) are mapped thereon, which are the transport channels. The forward access channel FACH is a downlink common channel and is used for transmitting control information and user data. The forward access channel FACH is shared and used by a plurality of mobile stations and is used for low-rate data transmission from a higher-level layer.
The paging channel PCH is a downlink common channel forming a pair with the paging indicator channel PICH as above and is used for transmitting the paging signal. The paging signal includes messages such as a mobile station ID (UE identity), a core network ID (CN identity), and a Paging case (Paging cause).
With regard to the downlink/uplink dedicated physical data channels DPDCH and the downlink/uplink dedicated physical control channels DPCCH, the downlink dedicated physical data channel DPDCH and the downlink dedicated physical control channel DPCCH are time-multiplexed in a time slot in the case of the downlink, and the uplink dedicated physical data channel DPDCH and the uplink dedicated physical control channel DPCCH are mapped to I-phase and Q-phase, respectively, in the case of the uplink. One or more downlink/uplink dedicated physical data channels DPDCH are allocated to a mobile station (spread code multiplexing) and used for the data transmission from a higher-level layer. Only one downlink/uplink dedicated physical control channel DPCCH is allocated to a mobile station and used for the physical layer control.
The acquisition indicator channel AICH is a downlink common channel forming a pair with the physical random access channel PRACH. The acquisition indicator channel AICH is used for the random access control of the physical random access channel PRACH.
The physical random access channel PRACH is an uplink common channel and has mapped thereon the random access channel RACH that is the transport channel. Random access is applied to use this channel for sending control information at the time of transmission. This channel is also used for data transmission (mainly at lower rate) from a higher-level layer.
The outline of the major physical channels and transport channels of the HSDPA mode will then briefly be described.
The high-speed physical downlink shared channel HS-PDSCH of the HSDPA mode is a downlink shared channel shared by a plurality of mobile stations and includes a high-speed downlink shared channel HS-DSCH (High Speed Downlink Shared Channel) of the transport channel for each mobile station. The HS-PDSH is used for transmitting packet data addressed to the mobile stations from a higher-level layer.
The HS-DSCH-related shared control channel HS-SCCH of the HSDPA mode is a downlink shared channel shared by a plurality of mobile stations and transmits to the mobile stations the information necessary for demodulating the high-speed downlink shared channel HS-DSCH (modulation mode, spread code) and the information necessary for error correction decoding process and a hybrid automatic repeat request HARQ (Hybrid Automatic Repeat reQuest).
The HS-DSCH-related uplink dedicated physical control channel HS-DPCCH is an uplink dedicated control channel and is used for transmitting downlink quality information CQI (Channel Quality Indication) representing a downlink radio propagation path status and ACK/NACK (Acknowledgement/Negative Acknowledgements) that is reception acknowledgement information corresponding to the hybrid automatic repeat request HARQ.
On the other hand, the evolution of the third generation radio access (Evolved Universal Terrestrial Radio Access, hereinafter, EUTRA) and the evolution of the third generation radio access network (Evolved Universal Terrestrial Radio Access Network, hereinafter, EUTRAN) are explored. The OFDM (Orthogonal Frequency Division Multiplexing) mode is proposed for the downlink of the EUTRA. The EUTRA technology applied to the OFDM mode is a technology such as adaptive modulation/demodulation error correction mode (AMCS: Adaptive Modulation and Coding Scheme, hereinafter, AMCS mode) based on adaptive radio link control (link adaptation) such as channel coding.
The AMCS mode is a mode of switching radio transmission parameters (hereinafter, AMC mode) such as an error correction mode, an encoding rate of error correction, a data modulation multi-valued number, a code spreading rate (SF: Spreading Factor) of time/frequency axes, and a multi-code multiplexing number depending on the propagation path statuses of the mobile stations to efficiently perform high-speed packet data transmission. For example, with regard to data modulation, the maximum throughput of a communication system can be increased by switching to the multi-valued modulation with higher efficiency such as from the QPSK (Quadrature Phase Shift Keying) to the 8-PSK modulation and the 16-QAM (Quadrature Amplitude Modulation) modulation as the propagation path status is improved.
With regard to disposition of the downlink physical channels and the transport channels in the OFDM mode, a method of multiplexing the physical control channel and the physical data channel in the same frequency band through the spread code multiplexing is proposed for the Spread-OFDM mode (see, e.g., patent document 1). In a method proposed for the Non Spread-OFDM mode (e.g., wireless LAN standard 802.16), the resources of the frequency axis (sub-carrier) and the time axis (OFDM symbol) of the OFDM are used to multiplex the channels in time/frequency through the time division multiplexing TDM (Time Division Multiplexing), the frequency division multiplexing FDM (Frequency Division Multiplexing), or a combination of TDM/FDM.
The technical requirements of the EUTRA/EUTRAN are proposed (see, e.g., non-patent document 4), which request spectrum flexibility for integration and coexistence with existing 2G and 3G services and request support for spectrum allocations to different size spectrum (frequency bandwidth, e.g., 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz, 20 MHz).
The technical information of the EUTRA is proposed (see non-patent document 5), which shows a method of frequency band position specification (center-frequency shifting) to be used for a mobile station capable of transmission/reception in different frequency bandwidths. Description will be made with reference to FIG. 37. When a base station supports a unique maximum frequency bandwidth, for example, a frequency bandwidth of 20 MHz and a mobile station supports a unique maximum frequency bandwidth, for example, a bandwidth of 5 MHz, the mobile station first uses the downlink synchronization channel DSNCH and the downlink pilot channel DPCH to perform cell search. Hereinafter, a group of mobile stations capable of transmission/reception in different frequency bandwidths, for example, Bn frequency bandwidths (Bn=1.25, 2.5, 5, 10, 15, and 20 MHz) is defined as a Bn mobile station class; a mobile station capable of transmission/reception in the Bn frequency bandwidth is defined as a mobile station of the Bn mobile station class; and a transmission/reception frequency bandwidth Bn of the mobile station defined by the Bn mobile station class is defined as a unique frequency bandwidth Bn of the mobile station.
Specifically, the mobile station detects a downlink synchronization channel DSNCH at 5 MHz, which is the center of the 20-MHz bandwidth, and then receives a downlink common control channel DCCCH. The downlink common control channel DCCCH includes transmission bandwidth information and frequency shift information for specifying frequency band positions to be used by respective mobile stations in different mobile station classes. The mobile station moves to the operating frequency band position in accordance with the control information to start data transfer. The downlink channels DSNCH and DCCCH will be described later.
As above, in the 3GPP (3rd Generation Partnership Project), the W-CDMA (Wideband Code Division Multiple Access) mode is standardized as the third generation cellular mobile communication mode and the service is sequentially started (see, e.g., non-patent document 1).
In the conventional mobile communication systems such as GSM (Global System for Mobile Communications) or W-CDMA, subscriber identifiers IMSI (International Mobile Subscriber Identity) are used for mobility management. The core network of the W-CDMA mode is configured based on the core network of the GSM. The movement managing method of the W-CDMA mode will be described with reference to FIG. 38.
An RNC (Radio Network Controller) (50) is a radio controlling device and a controlling device managing radio resources and controlling Nodes B (10). The RNC (50) controls handover, for example.
The Node B (10) is a logical node performing radio transmission/reception and is specifically a radio base station device. The Node B (10) is connected to a mobile station device 20 through a radio interface.
An SGSN (Serving GPRS Support Node) (30) is a control node for the packet switched service of the core network and includes a VLR (Visitor Location Register) (31) that manages subscriber information of visited subscribers.
Attach is mainly performed at the time of power-on of a mobile station 20. In a procedure for managing whether a terminal can receive an incoming call, an incoming call can be received in the attached state and an incoming call cannot be received in the detached state.
Location registration is performed if the mobile station moves a location registration area 40, and the subscriber information is downloaded from an HLR (Home Location Register) not shown in the procedure to the visited VLR (31).
The attach and the location registration process can concurrently be executed. When detecting a change in the location registration area 40 from broadcast information, the mobile station 20 makes a location registration request including a subscriber identifier IMSI to the VLR (31) of the SGSN (30) through the Node B (10) and the RNC (50). The VLR (31) downloads and allocates the subscriber information from the HLR as a temporary subscriber identifier to a TMSI (Temporary Mobile Subscriber Identity) and transmits a response message of the location registration to the mobile station 20.
Since the TMSI is used for identifying users over the air, security can be improved by hiding the IMSI as compared to the case of using the IMSI, and since the TMSI is used which has about half amount of information relative to the IMSI, an information amount can be reduced over the air.
A process procedure of paging will then be described with reference to FIG. 39. In mobile communication, if an incoming call exists for the mobile station 20, the mobile station 20 must be notified of the presence of the incoming call. The location information of the mobile station 20 is managed through the location registration area 40 in the network, and all the mobile stations are notified of the presence of the incoming call in a broadcasting manner in the location registration area 40 where the location of the mobile station 20 is registered. This procedure is referred to as paging.
The paging is performed by sending a paging request signal from the VLR (31) to all the RNC (50) containing the location registration area 40 registered in the visited VLR (31). Using the TMSI for the subscriber identifier in this case is advantageous as above from a viewpoint of security and signal amount as compared to the case of using the IMSI.
Since the mobile station 20 always monitors a channel for call-out in the case of the idle mode (standby state), the mobile station 20 can recognize the paging to the own station. The mobile station 20 returns a response to the network if the location registration area and the TMSI (IMSI) included in the paging request are identical to the location registration area and the TMSI (IMSI) stored in itself.
The outline of the major physical channels and transport channels of the W-CDMA will then briefly be described.
The paging indicator channel PICH is a downlink common channel forming a pair with the paging channel PCH (Paging Channel) of the transport channel corresponding to the secondary common control physical channel S-CCPCH having a paging signal mapped thereon. The PICH transmits the presence or absence of voice-call (CS: Circuit Switch) or packet-call (PS: Packet Switch) incoming-call information for incoming call groups that are groups of mobile stations.
When a mobile station belonging to an incoming call group #n is notified of the presence of an incoming call for the incoming call group #n through the paging indicator channel PICH, the mobile station receives the paging channel PCH in the corresponding radio frame mapped on the secondary common control physical channel S-CCPCH to determine the presence or absence of the incoming call to itself.
The paging indicator channel PICH is a channel set with the aim of reducing a discontinuous reception IR (Intermittent Reception) rate for improving battery saving in the mobile stations. The paging indicator channel PICH transmits a short paging indicator PI (Paging Indicator) for notifying the mobile stations of the presence or absence of an incoming call to the mobile stations belonging to the incoming call group #n and the mobile stations normally receive only the paging indicator PI in the standby state (idle mode). Only when the mobile station is notified of the presence of an incoming call through the paging indicator PI, the mobile station receives the paging channel PCH corresponding to the paging indicator PI.
The paging indicator PI is allocated to a plurality of the incoming call groups #n and a reception frequency per incoming call group #n can extremely be lowered. Therefore, the mobile station in the standby state (idle mode) may receive only the short paging indicator PI, which can extremely reduce the frequency of receiving the paging signal of the long paging channel PCH (having a large amount of information).
Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-237803
Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2004-297756
Non-patent Document 1: 3GPP TS 25.211, V6.4.0 (2005-03), Physical channels and mapping of transport channels onto physical channels. http://www.3gpp.org/ftp/Specs/html-info/25-series.htm
Non-patent Document 2: Keiji Tachikawa, “W-CDMA Mobile Communications System”, ISBN4-621-04894-5, P103, P115, etc.
Non-patent Document 3: 3GPP TR (Technical Report) 25.858, and 3GPP documents related to HSDPA specifications, http://www.3gpp.org/ftp/Specs/html-info/25-series.htm
Non-patent Document 4: 3GPP TR (Technical Report) 25.913, V2.1.0 (2005-05), Requirements for evolved Universal Terrestrial Radio Access (UTRA) and Universal Terrestrial Radio Access Network (UTRAN).http://www.3gpp.org/ftp/Specs/html-info/25913.htm
Non-patent Document 5: 3GPP R1-050592 NTT DoCoMo “Physical Channel Concept for Scalable Bandwidth in Evolved UTRA Downlink”.